//
// Copyright (c) 2019-2020 INRIA CNRS
//

#ifndef __pinocchio_autodiff_cppad_math_quaternion_hpp__
#define __pinocchio_autodiff_cppad_math_quaternion_hpp__

#include "pinocchio/math/quaternion.hpp"

namespace pinocchio
{
  namespace quaternion
  {
    namespace internal
    {

      template<typename _Scalar>
      struct quaternionbase_assign_impl<CppAD::AD<_Scalar>, false>
      {
        typedef _Scalar Scalar;
        typedef CppAD::AD<Scalar> ADScalar;
        template<typename Matrix3, typename QuaternionDerived>
        static inline void run(Eigen::QuaternionBase<QuaternionDerived> & q, const Matrix3 & mat)
        {
          typedef
            typename Eigen::internal::traits<QuaternionDerived>::Coefficients QuatCoefficients;

          typedef typename PINOCCHIO_EIGEN_PLAIN_TYPE(QuatCoefficients) QuatCoefficientsPlainType;
          typedef Eigen::Quaternion<ADScalar, QuatCoefficientsPlainType::Options> QuaternionPlain;
          QuaternionPlain quat_t_positive;

          ADScalar t = mat.trace();
          quaternionbase_assign_impl_if_t_positive::run(t, quat_t_positive, mat);

          QuaternionPlain quat_t_negative_0, quat_t_negative_1, quat_t_negative_2;

          quaternionbase_assign_impl_if_t_negative<0>::run(t, quat_t_negative_0, mat);
          quaternionbase_assign_impl_if_t_negative<1>::run(t, quat_t_negative_1, mat);
          quaternionbase_assign_impl_if_t_negative<2>::run(t, quat_t_negative_2, mat);

          // Build the expression graph
          for (Eigen::DenseIndex k = 0; k < 4; ++k)
          {
            ADScalar t_is_negative_cond1 = CppAD::CondExpGt<Scalar>(
              mat.coeff(1, 1), mat.coeff(0, 0), quat_t_negative_1.coeffs().coeff(k),
              quat_t_negative_0.coeffs().coeff(k));

            ADScalar t_is_negative_cond2 = CppAD::CondExpGt<Scalar>(
              mat.coeff(2, 2), mat.coeff(0, 0), quat_t_negative_2.coeffs().coeff(k),
              CppAD::CondExpGt<Scalar>(
                mat.coeff(1, 1), mat.coeff(0, 0),
                CppAD::CondExpGt<Scalar>(
                  mat.coeff(2, 2), mat.coeff(1, 1), quat_t_negative_2.coeffs().coeff(k),
                  t_is_negative_cond1),
                t_is_negative_cond1));
            q.coeffs().coeffRef(k) = CppAD::CondExpGt<Scalar>(
              t, ADScalar(0), quat_t_positive.coeffs().coeff(k), t_is_negative_cond2);
          }
        }
      };

    } // namespace internal

  } // namespace quaternion

} // namespace pinocchio

#endif // ifndef __pinocchio_autodiff_casadi_math_quaternion_hpp__
